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subsequently described the gall-inhabiting type of it, which I have termed gallæcola in a rather insufficient manner,[1] by the name of Pemphigus vitifoliæ. Dr. Fitch knew very little of the insect, as we understand it to-day. It was subsequently treated of by several American authors, and in January, 1867, Dr. Henry Shimer, of Mount Carrol, III, proposed for it a new family Daktylosphæridæ),[2] which has not been accepted by homopterists, for the reason that it was founded on characters of no family value.

All these authors referred to the leaf-louse described by Dr. Fitch, and never dreamed that the insect existed in another type on the roots. During the few years following our civil war a serious disease of the Grape-vine began to attract attention in France, and soon caused so much alarm that the Minister of Agriculture and Commerce in that country offered a prize of 20,000 francs for an effectual and practicable remedy; and a special committee was appointed to draw up a programme of conditions, and award the prize if it saw fit so to do.

The disease is known as pourridie, or rotting, the roots becoming swollen and bloated, and finally wasting away. There were no end of surmises and theories as to its cause, until Prof. J. E. Planchon, of Montpellier, in July, 1868, announced[3] that it was due to the puncture of a minute insect belonging to the plant-louse family (Aphididæ), and bearing a close resemblance to our gall-louse. The insect was subsequently described, by the same author, from the apterous form, under the name of Rhizaphis vastatrix, and not till September of the same year[4] when the winged insect was discovered, did he give it the name by which it is now so well known. In January, 1869, Prof. J. O. Westwood, of Oxford, England, announced[5] the receipt of both the gall and root-inhabiting types, from different parts of England and Ireland, and his inability to distinguish between the two. In the same article he announced having received the gall-making type from Hammersmith in 1863, and having described it by the name of Peritymbia vitisana, in a notice communicated to the Ashmolean Society of Oxford, in the spring of 1868, which communication was, I believe, never published. In the spring of 1869,[6] M. J. Lichtenstein, of Montpellier, first hazarded the opinion that the Phylloxera, which was attracting so much attention in Europe, was identical with the American insect described by Dr. Fitch. This opinion gave an additional interest to our insect, and I succeeded in 1870, while the Franco-Prussian war was at its highest, and just before the investment of Paris, in establishing the identity of their gall-insect with ours, through correspondence with, and specimens sent to. Dr. V. Signoret, of that city. During